text: An alloy of NiAl, known as IC-221M, is made up of nickel aluminide combined with several other metals including chromium, molybdenum, zirconium and boron. Adding boron increases the ductility of the alloy by positively altering the grain boundary chemistry and promoting grain refinement.  The Hall-Petch parameters for this material were σ = 163 MPa and k = 8.2 MPaˑcm. Boron increases the hardness of bulk NiAl by a similar mechanism.
  This alloy is extremely strong for its weight, five times stronger than common SAE 304 stainless steel. Unlike most alloys, IC-221M increases in strength from room temperature up to .
  The alloy is very resistant to heat and corrosion, and finds use in heat-treating furnaces and other applications where its longer lifespan and reduced corrosion give it an advantage over stainless steel. It has been found that the microstructure of this alloy includes NiZr eutectic phase and therefore solution treatment is effective for hot working without cracking.